gistfile1.py

    def post(self, computer_name):
        computer = self._get_computer(computer_name)
        
        data = json.loads(self.request.body)
        
        for application in data['applications']:
            result = self.database.query(
                '''
                INSERT INTO applications (
                    application_name, 
                    application_vendor, 
                    application_version
                ) SELECT 
                    %s, 
                    %s, 
                    %s 
                FROM dual WHERE NOT EXISTS (
                    SELECT * 
                    FROM applications 
                    WHERE 
                        application_name=%s AND 
                        application_vendor=%s AND 
                        application_version=%s
                );
                ''',
                application['name'],
                application['vendor'],
                application['version'],
                application['name'],
                application['vendor'],
                application['version']
            )